Patent GB-427922-A (GB)
Title: Manufacture of chromiferous dyestuffs
IPC: G01R11/36
Filed: 1934-04-03
Abstract: Mixtures of chromable azo dyestuffs, of which at least one is of the general formula <FORM:0427922/IV/1> wherein the hydroxyl and azo groups are in o-position to each other, n is 1, 2 or 3 and R is a naphthol residue, are chromed by treatment with a complex compound produced by the action of an organic compound containing hydroxyl groups on an alkaline suspension of chromium hydroxide.  The chromable azo dyestuffs not of the above general formula may be, for example, such as are derived from a diazotized amine of the benzene or naphthalene series and an arylamine, phenol, pyrazolone, oxyquinoline, barbituric acid, acetoacetic acid derivative or o-carboxybenzoylacetic acid.  Specified compounds containing hydroxyl groups are polyvalent alcohols and phenols, e.g. glycerol or gallic acid, tanning agents, e.g. tannin, sugars, cellulose derivatives, e.g. sulphite waste liquor and lignins.  The chromed dyestuff mixtures give deep level navy blue dyeings, particularly fast to rubbing.  For dyeing wool the processes of Specifications 364,148 and 408,497 are advantageously used.  The following examples are specified.  (1) A mixture of the dyestuffs, 1 : 2 - aminonaphthol - 4 - sulphonic acid --> 1 - naphthol, and 1 : 2 - aminonaphthol-4-sulphonic acid --> 2-naphthol is stirred and heated with water and a chromite solution containing glycerol, caustic potash and chromium hydroxide, the heating being for 2--3 hours at 75--80 DEG  C. and then for 2--3 hours at 90--100 DEG  C.; the solution is then diluted with cold water, dilute hydrochloric acid is added until the reaction is only weakly alkaline and the dyestuff is extracted by salting out or by filtering and evaporating in vacuo; the product dyes wool a fast navy blue.  (2) A mixture of the dyestuffs, 1 : 2 - aminonaphthol - 4 - sulphonic acid --> 2 - naphthol, and 1 : 2 - aminonaphthol - 4 - sulphonic acid --> 1 - phenyl - 3 - methyl - 5 - pyrazolone is stirred and heated with an aqueous solution containing sugar, caustic soda and chromium hydroxide, the heating being for 3 hours at 75--80 DEG  C. and then for 8 hours at 80--90 DEG  C.; the solution is then diluted, neutralized and filtered and the dyestuff is salted out; it dyes wool a fast navy blue.  (3) A similar product is obtained by treating similarly a mixture of the dyestuffs, 1 : 2 - aminonaphthol - 4 - sulphonic acid --> 2 - naphthol, and 2 - aminophenol - 4 : 6 - disulphonic acid --> 2 - naphthol.  (4) Wool is dyed a very fast navy blue by treatment for 10--15 minutes in dilute sulphuric acid at 60 DEG  C., adding the dyestuff of (1), continuing treatment at 60 DEG C. for 30 minutes, heating gradually to boiling, adding more sulphuric acid and boiling for 30--45 minutes.  (5) Wool is similarly dyed by treatment for 10 minutes in dilute formic acid at 85--90 DEG C., adding the dyestuff of (2), boiling, adding more formic acid, boiling for 20--30 minutes, adding sulphuric acid, boiling for 30 minutes, and boiling for 75--90 minutes with gradual addition of more sulphuric acid during 20 minutes.  (6) Wool is similarly dyed by treatment in a bath containing sulphuric acid, benzene sulphonic acid or its sodium salt and the dyestuff of (3) with rise of temperature to boiling from 60--70 DEG  C. during 30 minutes and continued boiling for 60--75 minutes.  (7) Loaded or unloaded silk is dyed a fast blue by treatment for 45--60 minutes at 80 DEG  C. in an acetic acid solution of the dyestuff of (1).  Specifications 297,331, [Class 2 (iii)], and 384,767 also are referred to.